Spring
Watch local soil temperature and late frost risk before moving tender starts outside.
Regional Climate Guide
Plant by your zone, then check the region
A USDA zone screens winter cold tolerance. Your region adds summer heat, rainfall, frost timing, wind, soil, and the length of the usable season.
US Growing Regions
0 regionsRegions that include Zone 13
Two yards can share a hardiness number while receiving different rain, summer heat, wind, and frost windows.
USDA Reference
Read the winter temperature bands
Each full zone spans 10°F. Local a and b subzones divide that band into 5°F steps.
Temperature based
The number comes from average annual extreme minimum temperature, not an average winter day.
Useful for perennials
Trees, shrubs, and returning perennials need a winter band that matches their cold tolerance.
One part of the site
Summer heat, humidity, rainfall, drainage, and microclimates can still remove a plant from the shortlist.
Frost Calendar
Zone and frost dates answer different questions
Use the ranges below as regional planning windows. A local extension source gives the closer date for your address.
Growing Season Contrast
Count usable days, not warm-zone assumptions
A long season can support repeated sowings. A short season needs fast varieties, transplants, or protection.
Seasonal Planning
Use the zone in a full-year sequence
Summer
Heat, rainfall, and root-zone moisture decide whether a cold-hardy plant can stay healthy.
Fall and winter
Finish establishment before the ground freezes and protect roots during temperature swings.
Use Your Result